1. Field of the Invention
The present invention relates to a power conversion system in an electronic device, and more particularly, to a power conversion system capable of rapidly outputting a power with a stable voltage value via combining voltage conversion circuits with different features.
2. Description of the Prior Art
Generally, all electronic devices equip with power conversion systems for converting a voltage of an external power to a workable voltage of the load circuit. For example, a liquid-crystal display (LCD) may equip with a charge pump for converting the voltage of the external power (e.g. 2.8 volts) to a voltage capable of driving the internal display components (e.g. 6 volts or 15 volts) and outputting the converted voltage to the source driver and the gate driver to drive the display components of the display panel to display different brightness.
Moreover, the voltage conversion circuits have different features due to different circuit structures. For example, the charge pump is a capacitor type booster. When the output loading is smaller, the voltage value of the output voltage of the capacitor type booster is more stable (i.e. the ripple of the output voltage is smaller). However, the capacitor type booster needs more time for increasing the voltage value of the external power to the workable voltage due to the small output current. In addition, the inductor type booster has the greater output current to drive the load circuit and can rapidly increase the voltage to the workable voltage of the load circuit. However, the voltage value of output voltage of the inductor type booster is more unstable (i.e. the ripple of the output voltage is greater).
In such a condition, since the prior art only configures a single kind of voltage converting circuit to convert the power required by the load circuit in the electronic device, the power with workable and stable voltage value cannot be outputted to the load circuit due to the features of the power conversion circuit. Thus, how to rapidly provide the power with the stable voltage value to the load circuit becomes a topic to be discussed.